Such a method is disclosed in U.S. Pat. No. 5,083,039, which describes an AC induction generator connected to a power converter. The torque of the generator is controlled using a PI regulator operating utilising field orientation. The power converter is then controlled to provide stator currents which result in the desired torque. This enables the controller to fully eliminate an error in a stationary state. One drawback with such a system however, is that it will be relatively complex.